Instructions
Construct a levee system using heavy machinery around large rivers that flood often. Study historical flood patterns to determine how extensive the size of the levees need to be. Rock and dirt are adequate material for earthen levees, though concrete levees are sturdiest and have good longevity.
Build reservoirs and retention areas to catch floodwater using steel frames and concrete. A professional construction contractor will be necessary to complete a job of this scale. Once complete, the reservoir managers can capture and release excess water gradually, preventing a more serious flood downstream.
Improve and maintain modern drainage networks like storm sewers and culverts. Clear any debris on a regular basis. Consider redesigning the system in areas that still tend to fill with water.
Straighten and deepen waterways adjacent to flood-prone areas, a process known as "channelization." Dredging equipment and barges are required for this kind of work. Scoop material out of the river or stream bottom and move it elsewhere on the barges.
Pile sandbags on levees when water levels threaten to overtop them. Watch for weaknesses at the base of levees, and be ready to place sandbags on those places.
Prepare your home for flooding in the event all of the large-scale preventative measures fail. Keep paperwork in watertight containers. Anchor fuel tanks, and know how to shut off utilities.